(1) Field of the Invention
The present invention relates to a drill and a method of manufacturing a machined product.
(2) Description of Related Art
As a drill capable of forming, at a time, a stepped hole in which a diameter is varied in midstream and a chamfered hole whose opening is chamfered, a step drill is known (see JP 2007-7831 A for example).
However, a conventional step drill described in JP 2007-7831 A has a problem that discharging performance of chip is inferior. Hence, if a through hole is formed using the conventional step drill, the through hole is prone to be clogged with produced chip, and there is a problem that an inner wall surface of the through hole is damaged or a cutting edge becomes fractured.